DANIELS EXPERIMENTS AND CONCLUSIONS 



the same order ; 2, hollow-stemmed annuals unite, while 

 the pith is functional ; 3, with trees the union is easily made and 

 the swelling at the point of union is reduced to a minimum; 4. 

 root grafting of herbaceous plants is most successful ; 5, duration 

 of grafted plants is more or less modified by the graft, a, annuals 

 on biennials or perennials continue to be annuals, i. e., at the end 

 of the growing season they die and cause the partial or total 

 death of the stock; b, biennial grafts with rare exceptions remain 

 biennial on both biennial and perennial stocks and induce the death 

 of the stocks ; c, perennial grafts on annual or biennial stocks die 

 with the stocks, but may be used as grafts on perennial stocks 

 prior to this event. 6, herbaceous grafts are less resistant to cold 

 than are mature wood grafts; 7, time of flowering is slightly re- 

 tarded among annual grafts, and at least for the first year among 

 biennials and perennials ; 8, stock 

 .rtd cion are influenced reciprocally 

 sometimes cion controls stock, 

 sometimes vice versa, and some- 

 times both classes of cases may be 

 found in the one kind of graft but 

 with different specimens. 9, Cul- 

 tivated varieties grafted on wild ones 

 generally show deteriorated qualit 1 

 in the fruit ; 10, seed produced in 

 such cases (9, just mentioned), some 

 seedlings revert to the wild type and 

 largely lose value as food plants 

 hence it is concluded that inferior 

 stocks should not be selected for 

 grafting when seed is to h 

 saved for planting; 11, reserve 

 food of a stock is rarely utilized by the graft of a plant of another 

 family. 



Circulation of liquids in grafted plants presents two extremes 

 to consider: 1. cases where water absorbed by the stock passes 

 in small quantity into the cion; and 2, where it is abundant. In 

 the former (the commoner) the cion makes less vigorous devel- 

 opment but flowers and fruits more abundantly than in Case 2 

 where the vessels are larger, the sprouts more vigorous and the 

 flowers and fruits less abundant, as in the case of a tree too well 

 nourished. At first these phenomena are physical, but later chem- 

 ical changes modify the cell contents as shown by starch or sugar 

 formation under the influence of the graft in certain cases. 



217. Reciprocal influence of stock and cion. Daniel has dem- 

 onstrated both direct and indirect influences of stock on cion in 

 grafted plants. From his experiments he deduces that variations 

 in the graft may be due to changes in nutrition or may be specific ; 

 that is, they may appear in particular characters of stock and cion 

 more or less independently of environment. The effects of graft- 

 ing on the general nutrition may be shown in four ways. 



143 HANDY STYLE OF 

 TREE CALIPER 



